// 链表示例:
const a = {val: 'a'}
const b = {val: 'b'}
const c = {val: 'c'}
const d = {val: 'd'}
a.next = b
b.next = c
c.next = d

// 遍历链表
let p = a
while (p) {
    console.log(p.val)
    p = p.next
}

// 插入
const e = {val: 'e'}
c.next = e
e.next = d

// 删除e
c.next = d